The third generation partnership project (3GPP) releases 5 and 6 provide HSDPA and HSUPA for high speed transmissions in the downlink and uplink, respectively. For HSDPA and HSUPA operations, a Node-B dynamically allocates radio resources to a plurality of user equipments (UEs), and several physical channels are provided to the UEs.
There are two downlink physical channels and one uplink physical channel in HSDPA. The downlink physical channels include a high speed shared control channel (HS-SCCH) and a high speed physical downlink shared channel (HS-PDSCH). The uplink physical channel includes a high speed dedicated physical control channel (HS-PDCCH).
The HS-SCCH carriers downlink HSDPA control information. The downlink HSDPA control information includes a channelization code set, a modulation scheme, a transport block size, hybrid automatic repeat request (H-ARQ) process information, redundancy and constellation version, a new data indicator and a UE identity (ID). A UE is assigned with up to four (4) HS-SCCHs in a cell via radio resource control (KEG) signaling. The UE needs to monitor all of the allocated HS-SCCH(s) before receiving control information for HSDPA.
The HS-PDSCH carriers downlink HSDPA data packets. Based on the processing of the HS-PDSCH, (e.g., cyclic redundancy check (CRC) and H-ARQ processing), the UE sends a positive acknowledgement (ACK) or a negative acknowledgement (NACK) signal to the Node-B via the HS-DPCCH. The HS-DPCCH also carries a channel quality indicator (CQI).
There are three downlink physical channels and two uplink, physical channels in HSUPA. The downlink physical channels include an enhanced dedicated channel (E-DCH) absolute grant channel (E-AGCH), an E-DCH relative grant channel (E-RGCH), and an E-DCH H-ARQ indicator channel (E-HICH). The uplink physical channels include an E-DCH dedicated physical data channel (E-DPDCH) and an E-DCH dedicated physical control channel (E-DPCCH)
The E-AGCH carries an uplink E-DCH absolute grant, (i.e., a maximum power ratio between the E-DPDCH and a dedicated physical control channel (DPCCH)). The channelization code for the E-AGCH is signaled separately to each UE. The E-RGCH carries an uplink E-DCH relative grant. The E-HICH carries an E-DCH H-ARQ acknowledgement indicator, (i.e., ACK or NACK). The E-DPDCH carries uplink HSUPA data packets. The E-DPCCH carries transport format combination index (TFCI) information, a retransmission, sequence number (RSN) and a happy bit.
The following Tables 1 and 2 summarize the control information sent on the downlink for HSDPA and HSUPA, respectively, and the following Tables 3 and 4 summarize the control information sent on the uplink for HSDPA and HSUPA, respectively.
TABLE 1Information (number of bits) WhenFrequencyShared control channel (SCCH)Channelization code (7)Before data transmissionPer TTIModulation (1)Before data transmissionPer TTITransport block size (6)Before data transmissionPer TTIH-ARQ process informationBefore data transmissionPer TTI(3)Redundancy version (3)Before data transmissionPer TTINew data indicator (1)Before data transmissionPer TTIUE ID (16)Before data transmissionPer TTI
TABLE 2Information (number of bits) WhenFrequencyAbsolute Grant Channel (E-AGCH)Absolute grant - in terms of After rate requestDepends on thepower ratio (5)implementation (100's of ms)UE ID or group of UE (16)After rate requestSame as aboveH-ARQ process activationAfter rate requestSame as aboveflagRelative Grant Channel (E-RGCH)From serving cellsUP/Hold/DownFollowing ULPer TTItransmissionFrom non-serving cellHold/Down (1)Following ULPer TTI (only for transmission‘down’ command)UE ID (16)Following ULPer TTI (only for transmission‘down’ command)H-ARQ Indicator Channel (E-HICH)ACK/NACK (1)Following ULPer TTItransmission
TABLE 3Information (number of bits) WhenFrequencyDedicated Control Channel (HS-DPCCH)ACK/NACK (1)Following DL transmissionPer TTICQI (5)Following DL transmissionPeriodic (multi TTI or 160 msec as soon as HSDPA channel is est.
TABLE 4Information (number of bits) WhenFrequencyE-DCH Dedicated Control Channel (E-DPCCH)RSN (2)With UL data Per TTItransmission Happy bit (1)With UL data Per TTItransmission E-TFCI (7)With UL data Per TTItransmission Rate Request Information (on E-DPDCH)Logical channel ID (4)Periodic and event triggered defined by RRCUE buffer occupancyPeriodic and event triggered(13)defined by RRCUE Power headroomPeriodic and event triggered(7)defined by RRC